The present invention provides a solid preparation, in which the silicon fine particles is the major ingredient, and it also able to catalysis the hydrogen evolution. In one embodiment of the solid preparation, the major ingredient of the solid preparation is the silicon fine particles with the crystallite diameter in the range of 1- 100 nm and it has the hydrogen evolution ability above 3 ml/g when contact with the aqueous liquid at above pH 7. According to the solid preparation, the silicon fine particles catalysis the hydrogen evolution when contact with the aqueous liquid. Therefore, it is possible to induce the hydrogen evolution by the characteristic as above mentions (e.g., after oral administration and through the stomach, the hydrogen evolution will occur in the digestive tract for contacting the pancreatic secretion at above pH 7).本發明之一固體製劑係以矽微細粒子為主要成分且具有析氫能力。該固體製劑之一具體例，主要以結晶子直徑在1nm以上100nm以下的矽微細粒子為主要成分，且當與pH值7以上的含水液體接觸時，具有3ml／g以上的析氫能力。根據該固體製劑，當矽微細粒子與pH值7以上的含水液體接觸時會析出氫。因此，如果活用該特徵，例如，口服且通過胃以後，在消化道內因分泌胰液而使pH值達到7以上之區域，會促進氫之析出。
